Circuit breaker



M 14,1936. I... s. WALLE CIRCUIT BREAKER Filed Feb. '1, 19:55

.FH BMW 1...7.1.[122111 iii Inventor: L lwmlb/vi g: S.Wal 16,

His/Attorney 1 Patented July 14, 1936 UNITED-STATES PATENT mm;

2,047,843 oracUIr enema Ludwig s. Wall'e, Lansdowne, Pa, asaig nor to General;Electric Company, a corporation of New York hpplication February 1, 1935, Serial No. 4,448

sciaims. (arson-144) g I My invention relates to circuit breakers, more particularly to interrupting or are extinguishing j ydevices therefor and has-foran object the provision of a simple and reliable interrupting device of the compression chamber type.

In my copending application, Serial No.

1 66'7,856', filed April 25', 1933, entitled, Circuit breakers which is assigned to the same assignee as the present invention, I have disclosed and 1 broadly claimed a circuit breaker comprising a compression chamber provided with a. fixed contact, a cooperating contact movable between open and closed circuit positions with a snap action,

rand sealingmeans associated with the movable contact and the compression chamber arranged [wtoprovide for snap action of the movable contact x and substantially to seal the compression cham- .ber depends not only upon the volume of the 5"]; compression chamber and upon thef'magnitude {of the current interrupted but also upon'the efw Ufectiveness of the sealing means provided. The

; problem of effectively sealing the compression j chamber is complicated not only by "the magnitude of the pressure which may be of the order of 1000 pounds'per square inch, but'by the necessity I :or providing for snap action of: the movable con- 1 tact between its extreme open and closedcircuit I have found that it is desirable, es-- 35 positions.

'cpeciallywhen utilizing circuit breakers of this type to interrupt large currents at relatively high flvoltages, to provide an additional sealing means which is effective when the movable contact is 4 in open circuit position gas tightly to seal the compression chamber so asto prevent the leakfage of any gases therefrom. The provision of a such an auxiliary sealing means-will of course re- "suit in the attainment of higher pressures in a j,4 -shorter interval of time and consequently, in a quicker interruption of the arc without burning bf the contacts. Accordingly, it isa further obect of my invention to provide a circuit interrupting device of the compression chamber type 50 provided with valve means for gas tightly seal- [ing the compression chamber when the movable contact is in open circuit position. carrying out my invention in one form, I ["provide a circuit breaker having a compression ss 'chamber for enclosing a fixed contactlland a relatively movable contact, the movable contact being provided with a shoulder arranged to seat against a wall of the compression chamber when thev movable contact is in open circuit position, gas tightly to seal the compression chamber. Means are also provided for operating the movable contact between open and closed circuit positions with a snap action. More specifically, I

provide a compression chamber having an aperture in one wall thereof for supporting and guiding a reciprocally movable contact, means asso-, ciated with the apertured wall and the movable contact for substantially sealing the compression chamber during movement of the contact be tween open and closed circuit positions, and means comprising a valve seat formed in the wall of the compression chamber and a valve head carried by the movable contact for gas tightly sealing the compression chamber when the movable contact is in its open circuit position, the

volume of the compressionchamber being of such 20.

magnitude that the gas entrapped at atmospheric pressure in the chamber is heated by the arc, formed between the contacts upon interruption of a predetermined, maximum current to such an extent that gas pressures are generated in the chamber sufiiciently high to efiect extinguishment of the arc, i. e., gas pressures of the order of 1000 pounds per square inch.

For a. more complete understanding of my invention, reference should now be had to the drawing in which Fig. 1 is a plan view of a circuit breaker provided with an interrupting device embodying my invention. The cover of the circuit breaker has been removed and certain parts have been omitted in order to illustrate the operating mechanism therefor. Fig. 2 is a sectional elevational view taken along line 2.2 of Fig. 1, and Fig. 3 is a partial, detailedsectional view of one end of the interrupting device with the movable contact shown in open circuit position.

Referring now to the drawing, I have shown my invention in one form as applied to a multipole circuit breaker comprising a base l0 formed of molded insulating material and arranged to support a plurality of improved interrupting or are extinguishing devices ll embodying my invention, an operating mechanism indicated generally by the reference numeral l2 and a unitary trip device'indicated generally by the reference numeral l3.

Each of the interrupting or are extinguishing devices ll comprises a pressure resisting cylinder I 4 preferably formed of brass or of an alloy, commonly known as Everdur, one form of which may be composed of 93% copper, 3% silicon and 1% manganese. Within the cylinder I4, I provide a fixed contact l5, a reciprocally movable contact IS, the abutting ends of which contacts are preferably formed of suitable low resistance material, such as silver-molybdenum, for example, and a cylindrical liner ll of kerosenefree fiber. In order to provide a gas tight closure for one end of the cylinder l4 and a rugged insulating support for the contact I5, a plurality ofinsulating bushings l8 and I9 and a cupshaped member 20 of suitable material such as soft copper, are arranged between an annularly extending portion 2| on the contact I5 and an inwardly extending flange 22 on one end of the cylinder |4. One end of the contact I5 is threaded as indicated at 23 and a nut 24 is provided for cooperation therewith, a corrugated washer 25 of insulating material being interposed between the nut 24 and the flange 22. It will be observed that the working surfaces of the flange 22 and the annularly enlarged portion 2| are beveled so that when the nut 24 is tightened down on the threaded end of the contact IS, the insulating bushings l8 and I9 and the washer 25 will be wedged into place to form a rigid support 'for the contact l5 and a gas tight closure for one end of the cylinder I4. It will also be seen that the soft copper member 20 will be spread by the annular portion 2| to form a gas tight seal between the cylindrical liner l1 and the contact l5, and to longitudinally fix the liner relative to the cylinder l4.

Closure means arealso provided for the other end of the cylinder H which comprise a cylindrical cap 26 threadedly engaging the cylinder l4 and provided with a sealing gasket 21 arranged to form a gas tight seal between the cap and the cylinder. Threadedly eng i g the cylindrical cap 26 is a plug or ring 23 in which the movable conductor I6 is slidably journaled. In order to substantially seal this end ,of the cylinder |4 while at the same time providing for snap action of the movable contact I6, I provide a. plurality of flexible washers 29 and 30, the washer 30 being provided with an inwardly projecting cylindrical extension for exerting a. wiping action on the movable contact l6 when the contact is operated to open circuit, position. In addition to its function as a sealing means between the end closure of the cylinder I4 and the movable contact IS, the washer 30 serves the additional purpose of preventing the deposit of metal vapor on the movable contact, a certain amount of which is produced when the circuit breaker interrupts currents of large magnitudes. In addition to the washers 24 and 3!! for substantially gas tightly sealing the compression chamber during movement of the movable contact I6, it is also highly desirable to provide means for entirely gas tightly sealing the compression chamber when the movable contact I6 is in its open circuit position. Accordingly, I provide a conical valve seat 3| in the inner face of the cylindrical cap 26 and an annularly extending shoulder 32 on the movable contact 6. When the movable contact is in its extreme open circuit position the shoulder 32 engages the valve seat 3|, as shown in Fig. 3, to provide a gas tight seal for this end of the compression chamber. It will be observed that in the embodiment shown the valve seat 3|is formed in a. separate member 33 which is supported in the cylindrical cap 26. This member 33 may be special heat resisting material SUCh'H-S stainless steel, or kerosene-free fiber in order to preventwelding of the movable contact to thevalve seat. For low voltages, as for instance voltages below 440 volts, it may be desirable to form the valve seat 3| directly in the face of the cylindrical cap 26.

It will, of course, be apparent that the movable contact |6 may be supported entirely within the compression chamber and operated between open and closed circuit positions by suitable reciprocal operating means extending through a wall of the pressure resistant casing, in which 7 case a shoulder corresponding to the shoulder 32 would be provided on the reciprocal means for cooperation with the valve seat 3| gas tightly to seal the compression chamber. r

The electrical circuit for each pole of the circult breaker is substantially the same and may be traced from one of the terminal members 34 arranged at one en of the base In to the fixed contact 5 by way of the conductor 35, which is clamped to the fixed contact l5 by a nut 36,

through the contacts l5 and I6, across the op- I eratingmechanism indicated generally at |2 by way of the flexible conductors 31, and through the trip device indicated generally at l3 by way of the conductors 38 and 39 to a terminal member 40. It will be observed that the movable contact l6'is not insulated from the metallic cylinder l4 and in order to provide sumcient creepage distance between the fixed contact I5 and the metallic cylinder l4, thewasher 25 is corrugated as shown, and the inner diameter of the cylindrical liner I1 is stepped as indicated, one end of the liner being spaced from the metallic cylinder l4 as shown at 4|.

Suitable insulating barriers are provided for preventing flashover or short circuit between the individual poles of the circuit breaker, the barmember l0 and extending from the respective opposite ends thereof to the operating mechanism l2 and the trip device |3, respectively,

which are provided with insulating barriers 44 v and 45, respectively, arranged substantially in alignment with the barriers 42 and 43.

Although any suitable mechanism may be provided for operating the movable contacts |6 between open and closed circuit positions with a snap action, either individually or simultaneously, I have shown for purposes of illustration an operating mechanism for simultaneously actuating all of the movable contacts l6 of the type described and claimed in a copending application of Leonard J. Linde, Serial No. 5,036, filed February 5, 1935, entitled Circuit breakers, which application is assigned to the same assignee as the present invention.

'the interrupting or are extinguishing devices II on a frame which comprises a pair of spaced supporting walls 46 and a supporting block 41, the walls and the block being mounted on one of the metallic cylinders l4 and suitably fastened thereto as by the screws 48. Each of the supporting walls 46 includes an elongate portion extending along the cylinder I4 and a laterally extending portion which overhangs the end of the cylinder I4 adjacent the movable contact l6. Extending between the overhanging portions of the supporting walls 46, a plurality of pivot pins 49, 50 and 5| are provided for respectively supporting a pair of spaced-parallel arms 52, a U- v g 12,047,a4s operating member 58 and a pair of three- I pointor substantially triangular shaped toggle links 54.

tends through a suitable aperture 58 in the circuit breaker cover 51, and the adjacent ends of the spaced arms 52 opposite from'the ends supported from the pivot pin 48 carry an operating pin 58,

the ends of which respectively extend through suitable slots 58 in the toggle links 54 In order ,to brace the spaced arms 52 andto maintain them in proper. parallel relation, a pair of cross" f pin'sj'68 and 6| are provided extending therebetween. These pins are omitted in Fig. 1 in order to simplify the drawing.

' Connected to each of the substantiallytrix angular toggle links 54 is a second toggle link 62,

the other end of which pivotally engages a pin' 63 which is supported by the legs of a U-shaped member 64, the yoke portion of which surrounds rigidly connected to a pivoted crossbar 65..

The erossbar 65 is journalled at its ends in a pair of bearings 66-fastened to the base l8 and'extends across the three poles of the circuit breaker for simultaneously operating all of the contacts l6 between open and closed circuit position, each of I the, contacts l6 being connected thereto by means or a resilient lost-motion connection which infcludes a pin 61 carried by the legs of a U-shaped operating finger 88 and extending through a. slot 68in a block 18 which is rigidly secured, as by a press fit, to the extending end of the movable contact I 6. As will be seen, the extendingend -.[of the movable contact I 8 is drilled as indicated at 'Ilto provide a housing for a compression, spring meme end of which bears against the contact 7 l6 and the other end of which bearsagainst the 'pin6'l. It will vbe observed that as the toggles each comprising the links 54 and 62 a're-concurrently made or broken, the cross bar 65 ,is'

rotatedand consequently the movable contacts lli 'are, operated between open and closed circuit I positions. a v

,In order to make and break the toggles with a snap action, a pair of overcenter spring devices are-provided. Although any suitable type of overcenter spring device may be provided each oflthe two devices shown comprises an inverted U-shaped frame 14, one end of which is pivotally connected to the operating pin 58 carriedfby the switch arms 52, and a yoke'membe'r 15 carried by apin16 which is carried by and extends laterally from the U-shaped operating member 53, Ar-

ranged within each U-shaped frame 14 isa pair of compression springs 11, the respective ends of which bear against the end portion of the frame and against a movable plate I8 arranged between the legs of the frameand carried by a pair of plungers 18, the oppositeends of which extend slidably through the end of the frame 14 and are fastened to the supporting yoke 15' carried by the pin 16. It will be apparent that the springs I! are arranged to resist relative movement between the yoke 15 and the frame 14 in the direction of the plungers l8 and tending to further operate them: and act as an extremely strong tension spring connected between the operating member 53 and the operating pin 58. i

The circuit breaker is also arranged forlautomatic operation in response to abnormal current conditions and accordingly, the operating mechanism is provided with a U-shaped tripping member 88' pivotally supported on the pin 58 and'nor- 1 many latched in the position shown in Fig. 2

by the trip device l3, the latching portion of which engages the yoke portion 8! of the tripping member. The tripping member 88 is provided, I The U-shaped operating member 53 isprovided with an insulating handle which extripping'member 88 from its latched to its tripping position, a pair of straps 88 is provided,

vention.

, in the path ofthe tripping member 88.

operating member is moved from its normal latched position in order to move the triangular togglelinks 54 about the pivot 5| to break the toggles and operate the contacts l6 to open circuit position. In order quickly to move the each of which is connected between a pin 84 on the tripping member 88 and a movable thrust bar 85'arranged in the slots 86in the frame walls 46 and engaging the adjacent ends of a pair of 15 trlpping springs 81, the other ends of which are supported .by a stationary thrust bar 8-8. It will be observed than when the tripping member 88 is in the latched position shown in Fig. 2 of the drawing, the tripping springs 81 will be com- 20 pressedand will therefore be effective upon the release of thetripping member to operate the tripping member in a clockwise direction about its pivot point 58, thereby causing the fingers 82 to engage-the operating pin 58. The force 25 exerted by the tripping springs 81 is sufficient to move the operating pin 58 downwardly as seen in Fig. 2 against the force exerted by'the overa center springs I1, and thereby to break the toggle and move the contacts [6 to their open circuit 30 positions. The tripping member 88 may bereturned to the latched position shown in the drawing after an operation thereof to trip the circuit breaker, by moving'the handle 55 downwardly, the operating member 53 being provided with a shoulder 88 which is' arranged to cooperate with a shoulder 88 on the tripping member. 1

Any suitable trip device may be provided for releasably latchingthe tripping member 88 in its latched position and for releasing the tripping member upon the occurrence'of abnormal current conditions. For best operation, however, I prefer to use a trip device of the type described and claimed in a copending application of John L. Lappin, Serial No. 4,659, filed February 2, 1935, entitled Circuit breakers, which application is assigned to the same assignee as the present in- This trip device l3 may be described for the purposes of the present application as comprising a sub-base 8| suitably fastened to the cir cuit breaker base l8, the before-mentioned insulating barriers 45 being formed integral therewith. Supported centrally of the sub-base- 8| is a frame comprising the spaced walls 82 between which are supported a latch plate 83, pivoted at 831;, a U-shaped impact member 84, pivoted M8411, and a U-shaped reset member 85, pivoted at 85a. The latch plate 93 is provided with a finger 85 arranged to engage the yoke "portion 8| of the tripping member 88 in latch-,

.portion 81 to provide a striking surface for engaging a portion of the latch plate 83 nested therewith. Each leg of the impact member 84 carries a pin 88 extending through a slot 88 in one of the supporting walls 82 and arranged to engage one of the two cam fingers I88 which 7 constitute the legs of the U-shaped reset'member 85., the yoke portion or which is interposed Suitable springs l8l are provided for operating the impact member 84 about its pivot in a counter- -by cause the overturned portion '91 to strike the latch plate a hammerlike blow and thereby move the latch to release the tripping member 80, and a'pair of resetting springs I02are arranged to operate the reset member 95 about its pivot to return the impact member 91 to the position shown in the drawing after each operation thereof to striking position.

The impact member 94 is normally held in the positionshown in the drawing by a tripbar I03, pivoted at I03a, which extends across the. three poles of the circuit breaker and is. normally biased by a spring I04 to engage a finger I05 on the impact member and thereby hold the impact member against movement on its pivot by the springs IOI. Associated with each pole of the circuit breaker is a thermal and a magnetic device for moving the trip bar I03 about its pivot in a counterclockwise direction as viewed in Fig. 2 to release the impact member 94. Each thermal device comprises a bimetallic element I06 arranged to be heated in accordance with the current through the associated pole of the circuit breaker and adapted when heated to engage an adjustable insulating button I01 carried by the trip bar I03 to move the trip bar about its pivot. As shown, each of the bimetallic elements has the shape of an inverted U and is connected in the circuit of its associated switch pole so as to carry a portion .of the current. Each of the magnetic devices comprises a U,- shaped magnet I08 partially surrounding one of the conductors 39 and arranged to attract a common armature I09, pivoted at I03a; which extends across the three poles of the circuit .breaker and is provided with a finger H0 for engaging an adjustable pin III on the trip bar I03 in order to move the trip bar about its pivot in a counterclockwise direction as viewed in Fig.

2 to release the impact member when the armature is attracted by one or more 01 the magnets I08'.

It. will be apparent that upon the occurrence plate 93 with a hammerlike blow and release the tripping member 80, whereupon the tripping member will be moved bythe tripping springs 81 to open the circuit breaker contacts.

While I have shown a particular embodiment of my invention, it will be understood of course that I do not wish to be limited thereto, since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent oi the United States is:

1. An electric circuit interrupter comprising a pair of contacts one of which is movable bemaximum current is interrupted without detrimental burning of said contacts, means extending through a wall of said chamber for operating said movable contact, and valve means responsive to movement of said one contact associated with said operating means and said one wall for 5 as-tightly sealing said compression chamber when said movable contact is in open circuit position whereby said high gas pressures are quickly generated.

2. An electric circuit interrupter comprising a pair of contacts one of which is reciprocally movable between open and closed circuit positions, walls of pressure resistant material enclosing said contacts to form a compression chamber of such size that the gas entrapped at atmospheric pres- 15 sure in said chamber is heated by the are formed between said contacts upon interruption of a predetermined maximum current to such an extent that gas pressures are generated in said chamber sufliciently high to effect extinguishment oi' the 20 arc, said movable contact extending through one of said walls, a valve seat comprising an annular member formed of heat resistant material supported on said one wall surrounding said movable contact and a shoulder on said movable contact arranged to engage said valve seat for gas-tightly sealing said compression chamber when said movable contact is in open circuit position.

3. An electric circuit interrupter comprising a pair of contacts one of which is movable between 30 open and closed circuit positions, a compression chamber comprising a casing of pressure resistant material enclosing said contacts, said casing having a volume of such size that the gas entrapped therein at atmospheric pressure is heated by the 35 arc'forined between said contacts upon interruption of a predetermined maximum current to generate in said casing high gas pressures oi 1000 pounds per square inch -or'more whereby said mental burning of said contacts, reciprocal means extending through an aperture in said casing for operating said movable contact, and means comprising a shoulder portion on said reciprocal means for engaging said casing adjacent said 5 I aperture gas-tightly to seal said chamber when said movable contact is in open circuit position whereby said high gas pressures are quickly generated. I

a 4. An electric circuit interrupter comprising a pair of contacts one of which is reciprocally movable between open and closed circuit positions, walls of pressure resistant material enclosing said contacts to form a compression chamber of such size that the gas entrapped at atmospheric pressure in said chamber is heated by the are formed between said contacts upon interruption oi a predetermined maximum current to such an extent that gas pressures are generated in said chamber sufliciently high to effect the extinguishinent of 00 the arc, said movable contact extending through I one of said walls, means associated with said wall and said one contact for substantially sealing said compression chamber during movement of said one contact, and a shoulder on said movable con- 65 tact for engaging said wall gas-tightly to seal said chamber when said one contact is in open circuit position.

5. An electric circuit interrupter comprising a 'pair of contacts one of which is reciprocally mov- 70 able between open and closed circuit positions, walls of pressure resistant material enclosing said contacts to form a compression chamber oi such size that the gas entrapped at atmospheric presi sure in said chamber is heated by the arc formed 76 between said contacts upon interruption of a predetermined maximum current to such an extent that gas pressures are generated in said chamber Jsufliciently high to effect extinguishment of the are, means extending through oneioi' said walls I for operating said movable contact,,means asso- --ciated with said one wall and said operating means for substantially sealing said compression chamber during movement ofv said one contact,

d said operating means for gas-tight y saling and valve means associated with said one wall usaid compression chamber when said movabl I contact is in open circuit position.

6. An electric circuit interrupter comprising a pair of contacts one of which is reciprocally movable between open and closed circuit positions,

: walls of pressure resistant material enclosing said contacts to form a compression chamber of such {size that the gas entrapped at atmospheric pres- ;sure in said chamber is heated by the are formed between said contacts upon interruption of a l and a shoulder on said one contact for engaging said valve seat when said one contact is in open circuit position gas-tightly to seal said-comp sion chamber.

, '7. An electricclrcuit interrupter comprising a pair of contacts one of which is reciprocally movable-between open and closed circuit positions, a 5

cylinder of pressure resistant material surround ing said contacts, a cap for one end of said cylinder provided with an aperture for guiding said reciprocal contact, closure means for gas-tightly closing the other end of said cylinder, said closure 10 means including a support for said other contact,

.. means associated with said cap and said re--- ciprocal contact for-substantially sealingsaid one end of said cylinder during movement of said reciprocal contact, and valve means associated with said cap and said reciprocal contact for gastightly sealing said one end of said cylinder when said reciprocal contact is in open circuit position;

8. A circuit breaker comprising a pair of relatively movable contacts, resilient means for operating one of said contacts between 'open and closed circuit positions with a snap action, a compression chamber comprising a, casing of pressure resistant material enclosing said contacts, said v one contact extending through an aperture in said casing, means associated with Said casing and said one contact for substantially sealing said chamber, during the snap movement of said one contact, and valve means associated with said casing and said one contact for gas-tightly sealing said chamber when said one contact is in open circuit position. LUDWIG S. WALLE. 

